JPH0791251B2 - Phenylalanine derivative and its use - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel N- (β-chloro-4-methylcinnamoyl) -phenylalanine derivative and an absorption-promoting substance containing the derivative or a non-toxic salt thereof as an active ingredient. Regarding the agent, the purpose thereof is to impart or enhance absorbability to a drug such as insulin.

BACKGROUND ART Conventionally known phenylalanine derivatives as absorption promoters (see JP-A-59-190926), benzoylpiperazine derivatives (see JP-A-59-5115) and hydroxybenzoate derivatives. (Biochimi
ca et Biophysica Acta, 775, 269-271, 1984), etc., but it is desired to have the properties sufficiently required for practical use.

Problems to be Solved by the Invention For example, when a polypeptide drug such as insulin is orally administered, it is inactivated by various proteolytic enzymes in the digestive juice, or is not absorbed from the intestinal tract due to its high molecular weight. For these reasons, administration of these drugs is limited to injection. However, injection administration is a physical drop that gives patients long term treatment,
There is a great deal of psychological distress, and in recent years, development of absorption promoters with low toxicity that enable administration other than injection has been more desired.

The present inventors previously invented an absorption promoter mainly composed of a phenylalanine derivative (JP-A-59-190926 and JP-A-62-62).
See the specification of 53954. )did. In the insulin therapy for diabetes, the above-mentioned invention was clinically highly expected, however, in the insulin therapy requiring long-term continuous use, a smaller dose and a higher safety for the absorption enhancer. Is required.

Means for Solving the Problems The present inventors have completed the present invention as a result of continuing diligent research to solve the above problems.

That is, the present invention is a novel N- (β-
Chloro-4-methylcinnamoyl) phenylalanine and salts thereof Alternatively, it relates to a novel absorption enhancer containing at least one of these as an active ingredient. However, phenylalanine may be any of L-form, D-form, and DL-form.

The above N- (β-chloro-4-methylcinnamoyl) phenylalanine or a pharmaceutically acceptable salt thereof, for example, inorganic salts such as sodium, potassium, calcium and aluminum, ammonium, N-acetyl-glucosamine, arginine and lysine. Organic salt imparts absorbency,
As an enhancer, it can be administered orally or parenterally (for example, rectally) together with a pharmaceutically active substance. In the case of insulin, for example, it has an oral or rectal absorption promoting effect.

Already contained in the phenylalanine derivative of the present invention made by the present inventor, N- (α-fluoro-4-methylcinnamoyl) is expected to be particularly promising in practical use.
-L-phenylalanine can be mentioned.

The compound of the present invention has properties superior to those of the above-mentioned compounds in terms of both absorption promoting effect and safety as a result of its absorption promoting effect and safety test. That is, a smaller dose has a remarkable absorption-promoting effect and a higher LD ₅₀ value.

The absorption enhancer of the present invention may be used in the range of 0.1 to 2,000 mg, preferably 0.2 to 500 mg, per 25 units of pharmaceuticals such as insulin.

The absorbability-imparting agent and the pharmaceutically active substance may be used, for example, in the form of tablets, capsules, elixirs, microcapsules or suspensions.

N- (β-chloro-4-methylcinnamoyl) of the present invention
Phenylalanine can be administered to patients in need of treatment with the above-mentioned drugs in a dose range of 0.1 to 1,000 mg per patient, generally in several divided doses, in a total daily dose of 0.2 to 2,000 mg per day. The dose will vary depending on the severity of the illness, the weight of the patient and other factors recognized by those of skill in the art.

The typical combinations shown above are formulated into pharmaceutical compositions as discussed below. The compound or admixture of phenylalanine derivative or physiologically acceptable salt used in the present invention is about 0.2 to 500 mg together with physiologically acceptable vehicle, carrier, excipient, binder, preservative, stabilizer, flavoring agent, etc. It is mixed in the unit dosage form required for generally accepted pharmaceutical practice. The amount of active substance in these compositions or preparations is such that a suitable dosage in the indicated range is obtained.

Specific drugs that can be mixed with tablets, capsules and the like are as follows. Binders such as tragacanth, acacia, corn starch or gelatin; excipients such as microcrystalline cellulose; swelling agents such as corn starch, pregelatinized starch, alginic acid, etc .; lubricants such as magnesium stearate; Sweetening agents such as sugar, lactose or saccharin; flavoring agents such as peppermint, red oil or cherry, and when the dosage unit form is a capsule, a liquid carrier such as fats and oils should be added to materials of the above type You can Various other materials can be present as coatings and to otherwise modify the physical form of the dosage unit. For instance, tablets may be coated with shellac, sugar or both. A syrup or elixir may contain the active compound, sucrose as a sweetening agent, methyl and propylparabens as preservatives, a dye and flavoring such as cherry or orange flavor.

Especially for insulin, it is preferable to use an enteric preparation, for example, 8% of hydroxyphenylmethylcellulose.
An aqueous solution may be used as a pretreatment agent for coating, and a 10% aqueous solution of hydroxypropylmethylcellulose phthalate and a 3% aqueous solution of polyacetin may be used as coating agents, which may be used as an enteric preparation by a conventional method.

Examples Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1. Production of N- (β-chloro-4-methylcinnamoyl) -L-phenylalanine β-chloro-4-methyl synthesized according to the method described in the literature (J. Org. Chem, 40 , 3227 (1975). To 6.0 g (30.5 mmol) of cinnamic acid, 40.0 ml of thionyl chloride was added and stirred for 3 hours at 90 ° C. Excessive thionyl chloride was distilled off under reduced pressure, dried and then dissolved in 50 ml of acetone.

L-phenylalanine (5.8 g, 35.1 mmol) was added to 2N sodium hydroxide (19.1 ml, 38.2 mmol) together with water (4).
It is dissolved in a mixed solvent of 0.0 ml and 80.0 ml of acetone. While cooling to 10 ° C or lower, the acetone solution of β-chloro-4-methylcinnamic acid chloride prepared above was added to 2N sodium hydroxide.
Alternate with 16.8 ml (33.6 mmol) over 20 minutes. After stirring at room temperature for 30 minutes, the reaction solution is acidified with 2N hydrochloric acid, and 2000 ml of water is gradually added. Subsequently, the precipitated crystals are separated, dissolved in 200 ml of ethyl acetate and washed with 150 ml of water and 100 ml of saturated saline. The organic layer is dried over anhydrous magnesium sulfate, filtered and concentrated, and then recrystallized from ethyl acetate-n-hexane to obtain 7.0 g of N- (β-chloro-4-methylcinnamoyl) -L-phenylalanine. Melting point
White crystals at 168.5-169.5 ° C.

Elemental analysis value Analytical value C: 66.41, H: 5.20, N: 4.02, Cl: 10.4
8, calculated as C ₁₉ H ₁₈ NO ₃ Cl, C: 66.37, H: 5.28, N: 4.0
8, Cl: 10.31 Optical rotation ▲ [α] ²⁴ _D ▼ -14.2 ° (C = 1.0, methanol) Mass spectrometry (FD-MS) M ⁺ ＝ m / z343 Nuclear magnetic resonance spectrum ( ¹ H, 90MHz) Example 2. Preparation of N- (β-chloro-4-methylcinnamoyl) -D-phenylalanine In Example 1, instead of L-phenylalanine, D was used.
The same synthetic treatment as in Example 1 is carried out except that -phenylalanine is used to obtain 6.50 g of N- (β-chloro-4-methylcinnamoyl) -D-phenylalanine.

White crystals with a melting point of 168.5-169.5 ° C.

Elemental analysis value Analytical value C: 66.58, H: 5.47, N: 4.09, Cl: 10.3
Calculated as 6 C ₁₉ H ₁₈ NO ₃ Cl C: 66.37, H: 5.28, N: 4.08,
Cl: 10.31 Optical rotation ▲ [α] ²⁵ _D ▼ + 14.3 ° (C = 1.0, methanol) Mass spectrometry (FD-MS) M ⁺ ＝ m / z343 Nuclear magnetic resonance spectrum ( ¹ H, 90MHz) Example 3. Activity test in mice The absorption enhancer according to the present invention was suspended in 0.5% CMC-0.05M Tris-HCl buffer (pH 7.8), mixed with insulin, and fasted for 18 hours in a group of 5 animals. Female ICR-CD1 mice (5 to 7 weeks old) were orally administered 0.5 U / 10 g (body weight) of insulin and 3 mg / 10 g (body weight) of absorption enhancer, and after a predetermined time, blood glucose lowering rate (%) relative to the control group And the fold increase in blood insulin was measured.

The respective results are shown in Table 1 below.

In the numerical values of the effects, the upper row shows 1) blood glucose lowering rate (%), and the lower row in parentheses shows 2) fold increase in insulin.

Further, in the table, -indicates that no increase in blood insulin amount was observed.

As shown in Table 1, N- (β-chloro-4- of the present invention
Methyl-cinnamoyl) -L-phenylalanine and N- (β-chloro-4-methylcinnamoyl) -D-phenylalanine significantly reduced blood glucose levels over conventional products at low doses in the activity test with mice. The effect and the effect of increasing blood insulin level were shown.

Example 4. Activity test in dogs Absorption-enhancing tests in dogs of the absorption enhancer according to the present invention and a known absorption enhancer N- (α-fluoro-4-methylcinnamoyl) -L-phenylalanine were carried out for comparison.

That is, a male beagle dog (6-8 months old) fasted for 18 hours
Orally, a gelatin capsule prepared so as to contain 50 U of insulin / kg and 25 mg / kg of a sodium salt of an absorption enhancer was orally administered. The same two dogs were tested for each absorption enhancer.

After a predetermined time, blood was collected from the forearm peripheral vein of each dog and the serum glucose level was measured. The average value of the two animals was calculated, and the results are shown in FIG.

N- (α-fluoro-4-mailcinnamoyl) -L-
Compared to the serum glucose lowering effect of phenylalanine,
N- (β-chloro-4-methylcinnamoyl) -L-phenylalanine and N- (β-chloro-4-methylcinnamoyl) -D-phenylalanine showed a remarkable serum glucose level lowering effect with sustainability. It was

Example 5 Toxicity Test N- (α-Fluoro-4-methylcinnamoyl) -L-phenylalanine, a known absorption enhancer, and a predetermined amount of each of the two absorption enhancers according to the invention in 0.5% CMC sodium salt solution. The LD ₅₀ value was measured by suspending the cells in a suspension and orally administering to male ICR mice (10 animals per 4-week-old group) 2 weeks later. The results are shown in Table 2.

The numbers in the table indicate the number of survivors when a given compound was administered at 1.0 g / kg and 3.0 g / kg.

As shown in Table 2, N- (β-chloro-4-methylcinnamoyl) -L- of the present invention as compared to known absorption enhancers.
Phenylalanine and N-(beta-chloro-4-methyl cinnamoyl)-D-phenylalanine clearly showed equal or higher than LD ₅₀ values.

EFFECTS OF THE INVENTION From the above results, N- (β-chloro-4-methylcinnamoyl) -L-phenylalanine and N- (β of the present invention
It is understood that -chloro-4-methylcinnamoyl) -D-phenylalanine is more excellent and useful as an absorption enhancer of a pharmaceutically active substance, particularly insulin, in terms of effect and safety.

[Brief description of drawings]

FIG. 1 shows the results of the activity test in dogs based on Example 4.

 ─────────────────────────────────────────────────── --Continuing the front page Examiner Osamu Sato (56) References JP 62-53954 (JP, A) JP 63-258841 (JP, A)

Claims (4)

[Claims] 1. A phenylalanine derivative having the following structural formula. 2. The derivative according to claim 1, which is in the form of a salt. 3. An absorption enhancer containing a phenylalanine derivative having the following structural formula or a salt thereof. 4. The absorption enhancer according to claim 3, which is for insulin.